The nature of research on speech communication in asymmetrical interactions, such as those between a speech therapist and patient, is discussed and some general approaches to therapy are noted. The situation of the aphasic is then considered, in which intervention is particularly difficult due to the lack of some important aspects of interpersonal communication. A study of three interaction situations is then reported. In the study, the language of three individuals (speech therapist, teacher, and spouse) in interaction with an aphasic was analyzed for evidence of individual differences. The results are used to illustrate the importance of individual differences in communication style in the effectiveness of the interaction. Contains 10 references. (MSE)